NEET 2021 · PhysicsPrevious Year Question
A uniform rod (200 cm, 500 g) is balanced on a wedge at the 40 cm mark. A 2 kg mass hangs at the 20 cm mark and an unknown mass m hangs at the 160 cm mark. For equilibrium, m is: (g = 10 m/s²)
Answer: (B) 1/12 kg. Correct Answer (B): 1/12 kg Solution: Torques about the wedge (40 cm).
- A.1/6 kg
- B.1/12 kg✓
- C.1/2 kg
- D.1/3 kg
Correct Answer
(B) 1/12 kg
Solution & Explanation
Correct Answer (B): 1/12 kg Solution: Torques about the wedge (40 cm). CCW: 2·(0.40-0.20)=0.40. CW: rod 0.5·(1.00-0.40) + m·(1.60-0.40) = 0.30 + 1.20m. Set equal: 0.40 = 0.30 + 1.20m ⇒ m = 1/12 kg.
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